Transmissions for commercial vehicles normally feature twelve, sixteen, or more gears. These types of multi-speed gearboxes are usually configured as multi-group transmissions comprising a front-mounted group, a main group, or as the case may be a main gearbox, and a range group. In order to facilitate the complex shifting sequence resulting from the plurality of gears, most of these transmissions feature a shifting device automated by a gearbox actuator. Shifts in the front-mounted group and the range group can thereby be done pneumatically, while shifts in the main gearbox are performed manually by the driver of the vehicle or can be performed automatically by means of suitable electrohydraulic, electropneumatic, or electromotoric gear shifting devices, or by a combination of these actuators.
Motor vehicle transmissions of this type have several components that correspond to different functions, and which are often integrated into the gearbox housing. Such components can, for example, be actuators, or as the case may be gearbox actuators or sensors.
This results in the necessity for simple and cost-efficient assembly of these components, as well as the replaceabilty of individual components. In addition, superfluous interfaces should be avoided.
An automotive transmission is known from the applicant's DE 103 47 493 A1, with a housing, in which, or on which torque-transmitting components are provided including a shifting device that is arranged between the vehicle transmission and a motor that drives the gearbox. In addition, actuating elements are arranged on the housing for actuating the torque-transmitting elements, whereby the housing comprises an area extending in the direction of the shifting device, in which area a connecting plate that can be permanently fixed to the housing is provided, in which accommodations are provided for at least some of the actuating elements for activating the torque-transmitting components. The actuating elements are preferably parts of a gearshift of a main gearbox or a splitting change-gear transmission and/or a range group transmission of the motor vehicle transmission.
In constructions that are known from the state of the art, in which a separate component is provided on the gearbox housing, which contains the working cylinder of the actuating devices and correspondingly integrated path sensors, the additional components provided are the channel plate, the valve plate, magnetic valves, a speed sensor, and a control unit. These components are affixed inside the cover of the gearbox actuator, which is mounted in a large compartment in the gearbox housing. Disadvantageously, a special coupling to the shift rods is hereby required.
In addition, the automatization components of the clutch actuator, that is the magnetic valves and the sensor, are integrated into the clutch actuator, which results in the necessity of an external wiring harness for the control unit (ECU) and a separate air connection. Hereby, in order to exhaust the gear actuator, seal contact areas must be provided on the housing. Disadvantageously, non-return valves are necessary to prevent back coupling of the compressed air. An additional disadvantage of this type of construction is that noise-damping measures are necessary, such as a woven fabric liner with a cover.
The present invention is based on the objective of presenting a motor vehicle transmission, configured as a multi-group transmission, comprising a gearbox actuator, in which the cited disadvantages of the state of the art are avoided.